[MPlayer-users] Re: mencoder/crop => image distortion

[D Richard Felker III]

On Thu, Jul 31, 2003 at 11:17:30PM -0500, Jonathan Rogers wrote:
> The result is that most of the movies will look correct in any 
> player, though a few will look a little odd in anything but 
> MPlayer. It is very disappointing that the aspect tag isn't 
> widely respected. I was especially disappointed to discover that 
> ffdshow (the DirectShow filter that uses lavc) doesn't respect 
> it, though it allows the user to manually change the aspect. 
> Maybe the author just isn't aware of it, so perhaps I should 
> submit a bug report.

I'm not sure it's possible -- it may be a limitation of dshow. The
aspect from the mpeg4 header is only available after the first video
frame reaches the decoder, and I think dshow expects aspect to be
initialized *before* that. Early versions of mplayer had a similar
issue with width/height/etc. when correct values couldn't be obtained
from the container header, only from the actual video stream. That was
fixed with the (very complicated, but also very powerful and flexible)
vf init/config system.

Rich